Table 1.

Comparison of case and control subjects.

Variables	Controls N = 560	Cases N = 154	P value
Date of birth (range)	1946.7 (1916–68)	1947.2 (1919–66)	0.62
Diagnosis of breast cancer (range)
Year	1989.2 (1953–07)	1989.1 (1957–05)	0.96
Age	43.0 (26–68)	42.5 (27–66)	0.53
Chemotherapy	61.6%	66.8%	0.29
Radiotherapy	46.5%	50.7%	0.42
Type of surgery Mastectomy	63.3%	66.2%	0.57
Ovarian cancer diagnosis (range)
Year	N/A	1998.2 (1978–08)	N/A
Age	N/A	51.4 (35–75)	N/A
Tamoxifen treatment	20.7%	20.1%	0.89
Oral contraceptive use	55.5%	53.2%	0.67
Hormone replacement therapy	6.5%	4.6%	0.39
Parity
Mean (range)	2.2 (0–8)	2.0 (0–7)	0.16
Nulliparity	11.3%	13.6%	0.50

All p values were derived using the Student’s t test for continuous variables and the chi-square test for categorical variables.